1. Field of the Invention
The present invention relates to a plasma addressing display device and a method for producing the same.
2. Description of the Related Art
The development of a display device, such as a flat panel display, has been directed to small-screen, monochromatic and binary displays. Past this initial stage of the display device development, efforts are now directed to develop larger-screen, multi-color, grayscale and/or motion picture displays. The performance of the devices in this field has been steadily improved each year.
Hereinafter, the structure and the operation principle of a conventional plasma addressing display device 10, as one example of such a display device, will be described with reference to FIGS. 15 and 16A to 16F.
As illustrated in FIG. 15, the plasma addressing display device 10 includes a color filter substrate 50A and a plasma addressing substrate 50B, interposing a liquid crystal layer 46 which is provided by injecting a liquid crystal material therebetween. The display device 10 is further provided with a backlight 50.
The color filter substrate 50A includes a polarizer 41a, a transparent substrate 42a, a color filter 43, a transparent electrode line 44 and an alignment film 45a. On the other hand, the plasma addressing substrate 50B includes a polarizer 41b, a transparent substrate 42b, a partition wall 48, electrode lines (e.g., an anode 49A and a cathode 49C), a dielectric sheet (a thin transparent substrate) 47 and an alignment film 45b.
The plasma addressing substrate 50B includes a plurality of plasma discharge channels 50C each being a space enclosed by the transparent substrate 42b, two adjacent partition walls 48 and the dielectric sheet 47. The plasma discharge channels 50C each contain a noble gas, such as He, Ne, Ar and Xe, at a gas pressure of about 10 Pa to about 10.sup.4 Pa, preferably about 10.sup.2 Pa to about 5.times.10.sup.3 Pa. The transparent electrode line is linearly arranged so that the transparent electrode line 44 orthogonally crosses over the plasma discharge channel 50C, which is also linearly arranged but in a different direction. Each region where the transparent electrode line 44 and the plasma discharge channel 50C overlap each other corresponds to a picture element of the color filter 43.
Hereinafter, the operation of the plasma addressing substrate 50B will be briefly described with reference to FIGS. 16A to 16F.
Writing and holding of information are performed in the following manner.
First, as illustrated in FIG. 16A, a voltage of about 100 V to about 500 V is applied between the anode 49A and the cathode 49C, i.e., a voltage Ec of about -300 V to about -450 V is applied to the cathode 49C, thereby causing an electric discharge.
Throughout the accompanying figures, a black circle (.circle-solid.) and a white circle (.largecircle.) represent a negatively-charged and a positively-charged particles, respectively.
Then, a voltage Ed of about +50 V to about +100 V is applied to the transparent electrode line 44 of the color filter substrate 50A, as illustrated in FIG. 16B, thereby writing information, and then the electric discharge is discontinued so as to negatively charge the dielectric sheet 47 interface, as illustrated in FIG. 16C, thereby holding the written information.
On the other hand, in order to positively charge the dielectric sheet 47 interface, a voltage Ed of about -50 V to about -100 V is applied to the transparent electrode line 44 of the color filter substrate 50A, and then the electric discharge is discontinued, as illustrated in FIGS. 16D to 16F.
FIG. 17A illustrates a change over time of the voltage Ec, and FIG. 17B illustrates a change over time of the voltage Ed. In FIGS. 17A and 17B, time periods "a" to "f" correspond to FIGS. 16A to 16F, respectively.
The above-described conventional plasma addressing display device 10 has a low aperture ratio, and thus a low brightness, due to the presence of the electrode lines (e.g., the anode 49A and the cathode 49C). In order to mitigate such a problem, the backlight performance has to be improved, for example, which increases the cost of the device.
Japanese Laid-open Publication No. 6-222346 proposes a plasma addressing display device in which an insulative partition wall is provided on each electrode line. However, as described in paragraphs [0059] to [0062] on page 7 of Japanese Laid-open Publication No. 6-222346, one problem of the device of this publication is that the voltage to be applied to the electrode line is complicated.
Japanese Laid-open Publication No. 6-251719 proposes a discharge cell and a method for producing the same in which an anode is provided directly under a partition wall with a width larger than that of the partition wall, in order to increase the tolerance for the position of the electrode line, thereby facilitating the production of the device, and to increase the aperture ratio thereof. However, even the device of this publication can only realize an aperture ratio of about 40%.